Update 7:24 p.m.: From ComEd, there are eight outages in Cortland affecting 638 customers (about one-third of the town). The total number of customers out of power in DeKalb County now stands at 1,936.

Update 6:45 p.m.: About 1,500 ComEd customers are without power in DeKalb County, a ComEd spokesman said. That includes about 100 customers in Cortland and about 500 south of Route 30, with the rest sprinkled among DeKalb, Sycamore and the northern parts of the county.

ComEd spokesman Paul Callighan did not know the cause of the Cortland outage but said crews were on site. ComEd crews are working staggered 16-hour shifts throughout the storm to try to restore power as quickly as possible.

"We know outages will continue to occur as the winds continue to blow," Callighan said.

Customers can report power outages by calling 800-334-7661 or through www.ComEd.com or www.Facebook.com/ComEd. Spanish-speakers can call 800-955-8237.

Customers also can text "out" to 26633 to report their outage and receive restoration information.

DeKalb County's 13 plows are already on the road, with drivers expecting the northwest corner of the county will see snow first.

The county highway department's plows will run until 9 p.m. so the drivers can rest before hitting their routes again at 3 a.m., DeKalb County Engineer Nathan Schwartz said. Given the above-freezing temperatures and rain earlier today, a temperature drop could lead to black ice and a temperature drop coupled with snow could lead to slushy roadways.

"I think this is going to be one of those storms where you need to be ready for anything because you don't know what to expect," Schwartz said.

The drivers are experienced with their routes, so they are familiar with the areas that tend to experience drifting and need extra attention, Schwartz said.

"But we can't be everywhere at the same time, so of course everyone needs to use their winter weather driving," he said.

Update 2:25 p.m.: DeKalb's assistant director of public works cautioned drivers to slow down and be safe tonight.

"It's going to be one of those storms," said Mark Espy.

Espy is planning to have 16 large trucks circulating the city's main roads first and then subdivisions starting an hour before the snow storm is expected to hit. He's also keeping an eye on temperatures in Dixon and Rochelle.

The winds could cause drifting that makes three to six inches of snow feel like a foot. He expects crews will he working over night.

"It'll be an all-night thing," Espy said. "They're saying the snow is supposed to start around 4 or 5 p.m. The bulk of the participation will be over, but the wind will still be going."

Update 2:06 p.m.: The Sycamore Public Works Department has 15 people on hand to start plowing whenever the snow decides to arrive. The department has 14 snow plows that can spread salt, five pick-up trucks with plows and other machinery to handle the snowfall, Public Works Director Fred Busse.

Busse expected crews would spread salt before heavy snow started around 5 p.m. so long as the rain held off. Plowing during rush hour isn't always productive, as the plows sit in traffic along with passenger vehicles.

"It might be enough where we go out and salt for awhile, go home, and come back after the snow accumulates a little bit," Busse said.

Update 12:28 p.m: DeKalb County is now under a blizzard warning, which is in effect until midnight tonight according to the National Weather Service. Between 4-7 inches of snow is expected, along with wind gusts that will approach 55 miles per hour. The combination of heavy snow and high winds will create almost zero visibility at times.

The rain should change to snow early this afternoon and will be heavy at times. It should taper off and linger through the night.

DeKALB – The first measurable snow in more than 280 days is expected to create dangerous conditions as many people leave work today.

DeKalb meteorologist Gilbert Sebenste said there would likely be two to four inches of snow today with winds gusting between 50 and 60 mph.

The storm could be at its worst at about 5 p.m., with flash freezing causing black ice a strong possibility, he said.

“I would very strongly recommend that there is no travel between 5 p.m. [today] and 6 a.m. Friday,” Sebenste said. “It would be extremely unwise ... I cannot stress that enough.”

He said because of the temperatures and the wind, it would take less than an hour for wet surfaces to freeze.

Along with the low visibility caused by the blowing and drifting snow, Sebenste said the storm could also be dangerous because of tree debris.

Because of the long drought this summer, he said trees are weakened and more branches will come down during high winds and bad storms.

James Briscoe, superintendent of DeKalb School District 428, said area superintendents would go through their standard procedure of checking in with the transportation service companies about road conditions during morning runs before making any call on a closure.

“Whiteout conditions and black ice are two of the biggest concerns,” Briscoe said. “Unfortunately, we live in the Midwest where it snows and it blows.”

The expected snowstorm will also mark the end of a historical run of time between measurable snowfalls. Measurable snowfall, which is defined as one-tenth of an inch, has not occurred since March. The last snowfall generally happens in April and the first in November, Sebenste said.

“We have gone over nine months since we last saw measurable snow, that’s definitely the longest period ever,” he said.

The storm probably will not leave any holiday spirit behind, either. Sebenste said it would likely melt before Christmas Eve, with temperatures expected to be in the 30s during the weekend. At least an inch of snow is needed for a “white Christmas.”